simplify code using a list in python

I have a line of python code that basically asigns a integer to a string (one letter). Since I use if statements, it need a lot of code lines... Is there a way I could simplify my code using a list so that it doesn't take up 63 lines of code? Here's my code:

if character in " ":
character = 0
elif character in "Aa":
character = 1
elif character in "Bb":
character = 2
elif character in "Cc":
character = 3
elif character in "Dd":
character = 4
elif character in "Ee":
character = 5
elif character in "Ff":
character = 6
elif character in "Gg":
character = 7
elif character in "Hh":
character = 8
elif character in "Ii":
character = 9
elif character in "Jj":
character = 10
elif character in "Kk":
character = 11
elif character in "Ll":
character = 12
elif character in "Mm":
character = 13
elif character in "Nn":
character = 14
elif character in "Oo":
character = 15
elif character in "Pp":
character = 16
elif character in "Qq":
character = 17
elif character in "Rr":
character = 18
elif character in "Ss":
character = 19
elif character in "Tt":
character = 20
elif character in "Uu":
character = 21
elif character in "Vv":
character = 22
elif character in "Ww":
character = 23
elif character in "Xx":
character = 24
elif character in "Yy":
character = 25
elif character in "Zz":
character = 26
elif character in ".":
character = 27
elif character in ",":
character = 28
elif character in "?":
character = 29
elif character in "'":
character = 30
else:
character = 0

Put all of the characters into one big string where the characters' positions in that string are the values you want to assign. You can handle upper and lowercase letters by converting the input to lowercase first.